The construction of most shower floors typically consist of at least these components:
1) Shower subfloor. PA0 2) Shower pan. PA0 3) Mortar bed with or without aggregate. PA0 4) Shower drain with feature for creating a watertight seal to pan. The drain should also incorporate drainage openings at the same approximate level of the pan for the purpose of draining the mortar bed. These openings are also known as "weep holes". This type of drain is often called a "double seepage drain". PA0 5) Floor surfacing material, (most often ceramic tiles). PA0 A) Free flow of water from the mortar bed to the weep holes. PA0 B) Isolation of the weep holes from the mortar bed in order to keep the fine particles and more dense structure of the mortar bed from clogging up the weep holes. PA0 C) A much greater surface area of mortar bed available for water drainage into the weep holes, than the surface area of the weep holes alone would provide. PA0 D) Protection of the weep holes from aggregate or other particles falling into them and partially or completely obstructing them. PA0 E) Protection of the weep holes from a large piece of material covering the weep hole and effectively sealing it off. PA0 F) Convenience, low expense and ease in use for the installers so that the porous medium will be widely and properly used, therefore enabling the weep holes to perform as designed. PA0 G) A strong, dimensionally stable, and continuous support for the surrounding mortar bed and overlaying tiles, creating a floor with structural integrity.
All of these elements should work together to produce a quality shower floor providing years of service without leaks or a weak floor. Each component is further defined as follows:
1) A subfloor is usually a concrete floor or a wood floor. Wood floors are most often encountered in pier and beam construction. However, the type of subfloor is irrelevant to this invention. The subfloor is mentioned because it provides the base which all the other elements of this discussion rest upon or within. For the shower pan to drain most effectively the subfloor should be slightly sloped toward the drain so that fluids on top of the pan will flow toward the drain. The most common method of achieving this slope is by "skim coating" or "floating" the subfloor with a thin layer of suitable mortar prior to covering with the shower pan. This coat of mortar is trowelled to the proper grade to give the proper slope to the subfloor.
2) The shower pan is most often a tough plastic sheet 20 to 40 mils thick. The most common plastic pan is 40 mils thick and generally is available in rolls of 4, 5 or 6 feet width. Lead sheets are sometimes used, and occasionally copper sheets are used. In a small percentage of installations a trowellable liquid material is used which cures to form a waterproof membrane.
Other types of waterproofing exist, but by far the most widely used waterproofing for showers is the plastic sheet. It should be noted however, that the type of shower pan used is irrelevant. Any pan used in conjunction with a double seepage drain, will perform better if used with the invention disclosed herein.
One type of shower which commonly does not employ a drainage system such as the one discussed herein, is a shower commonly referred to as a "fiberglass shower". The fiberglass shower is normally a premanufactured unit where the floor is available as an integral or componentized part of the shower stall. The shower usually comprises a construction of resin and fibers. Normally this type of shower would not be considered a candidate for the use of the invention disclosed herein, since it would not typically use a double seepage drain.
3) The mortar bed comprises a sand and portland cement mixture which at the time of installation is placed over the shower pan as a damp, compactable, screedable, coarse material. It has a consistency much like that of a damp sand suitable for building a sand castle. It typically has three to six times as much sand as it does cement. It is not highly liquid or flowable like a concrete mixture typically seen poured into forms for a sidewalk or driveway.
The mortar bed material is often called a "dry pack" and has only enough water in it to hydrate the cement and make the mortar bed compactible. The mortar bed cures into a hard concrete base, suitable for supporting the overlaying tiles or other selected floor covering. Because of its large proportion of sand, the mortar bed remains very porous and will readily soak up water.
A mortar bed will typically vary in thickness anywhere from 3/4 inch to 3 inches thick depending upon the preferences of the installer, the subfloor condition, and the height of the top of the drain above the shower pan. The thickness (i.e. height) of the mortar bed at the outside edge of the shower floor typically will be thicker than at the area of the mortar bed adjacent to the shower drain. This provides slope to the floor so that water will flow on the surface of the floor towards the floor drain (top of the double seepage drain).
Standard procedure is to incorporate a wire or plastic reinforcing mesh into a mortar bed horizontally to help hold it together. Although this is widely practiced in the construction of large mortar beds such as found in floors of large commercial kitchens, it is not widely practiced in the construction of shower floors. This is probably due to the fact that it is inconvenient to install and the size of the floor in a shower is generally not much over three feet by four feet. However most manufacturers of tile setting materials still recommend reinforcing small mortar beds such as a shower floor.
The mortar bed serves two main purposes. The first is to provide slope to the floor surface so it will drain as already mentioned. The second purpose is to provide a bedding surface for the overlying floor material to rest upon and bond to. For this type of shower construction the most common floor surface material is a ceramic tile, marble tile or marble slab(natural marble or man made).
The mortar bed rests on top of the shower pan, relying on the shower pan for waterproofing the floor of the shower. The mortar bed is itself very porous, contributing nothing to the waterproofing of the shower. In fact, if it is not properly drained, the mortar bed actually creates a waterproofing liability.
The mortar bed quickly soaks up any water that contacts it and will hold a considerable amount of water until it becomes saturated. If the mortar bed is properly drained then this liability is minimized. However if the mortar bed does not drain well, it will become a reservoir of water.
Should the pan develop a small leak then this reservoir of water slowly but continually seeps through the leak flowing into the subfloor and surrounding area. This escaping moisture can decay and destroy many of the other surrounding materials such as wooden studs in the wall, sheetrock and the overlying paint, wall paper or tile, carpeting or other flooring, wooden base and trim, wooden subloors, etc. These types of repairs can be quite expensive necessitating complete replacement of the shower bottom and any other damaged or stained materials in the home or building.
Usually this type of leak will flow continuously even between showering since the mortar bed will saturate quickly but deplenish slowly if the mortar bed drainage system is not working well. That is, the mortar bed will quickly soak up water while the shower is being used. If a small leak is present it is possible to slowly deplete the reservoir without depleting the mortar bed entirely before the shower is used again.
A large leak is usually noticed rather quickly, before much permanent damage is done, particularly to structural components of the building. Small leaks such as the one addressed herein, can and often do go unnoticed for months or years before they are noticed. By then the rot and moisture have often caused a great deal of damage. This type of leak can also encourage mildew and fungus growth to occur in carpeting, wood and other building materials which may cause or aggravate allergies, respiratory ailments or other health problems.
A leak in the pan located near the top of the mortar bed should theoretically allow only a negligible amount of water to pass through, if the bed drains well. That is, the saturation level in the mortar bed should drop fast enough to "in effect" avoid the leak, if the bed is properly drained.
Thus it is vital for the mortar bed to drain effectively in order to avoid or minimize a leaking problem. There is a practice that has been recognized for decades that should properly drain the mortar bed, but it is not in wide use. The practice involves constructing the mortar bed in such a manner as to help water to flow from the mortar bed into drainage openings located at the base of the drain for the purpose of draining the mortar bed. This practice will be expounded upon after discussion of component #5.
4) Typically the drain is designed to fulfill three main purposes, (A) achieving a water tight connection to the shower pan, (B) providing drainage to the mortar bed and (C) draining the shower floor or other wet surface.
This type of drain is sometimes called a "double seepage drain". For the purpose of this application the term "double seepage drain" shall refer to any type of floor drain which has a means for "double drainage". That is, it drains the floor surface while also allowing water to seep from a "setting bed" into the drain. The "setting bed" is most often a mortar bed but in some situations the bed may comprise loose sand, aggregate or some other type of filler.
In addition the drain incorporates "drainage openings" designed into the drain collar. These openings are usually holes, grooves, slots or other openings formed through the drain collar, or occasionally in the drain neck. They are sometimes known as "weep holes". For the purpose of this application the terms "drainage openings" and "weep holes" may be used interchangeably. This is while acknowledging that in some drains the openings may be grooves or some other type of opening other than what might be considered a "hole". However the term "weep hole" is descriptive in that it describes an opening which allows water to "weep" from the mortar bed into the drain.
The collar attaches to the drain flange sandwiching the shower pan between them, which creates a water tight seal. Some contractors will caulk the area between the pan and drain flange before installing the collar over the pan in order to get a better seal. The weep holes allow water from the mortar bed to drain through the collar and into the drain. The water on the top of the floor surface runs down through the top of the drain.
5) The floor surface material, as previously mentioned, is most often a tile of some type but there are other suitable materials. The tile or other floor material allows water to get into the mortar bed as it soaks through the grout joints between the tiles and at the intersection between the wall and floor. A commonly used tile for shower floors would be a 2 inch square tile, 4 inch hex shaped tile or other similar sizes.
Up until now, the best method of installing the mortar bed was to first place a pile of gravel or small pieces of broken tile around and above the weep holes located on the drain collar, prior to placing the mortar bed. This pile of aggregate served to provide better access for free water flow from the mortar bed into the weep holes, than just placing mortar directly over the weep holes. The aggregate would effectively allow more surface area of the mortar bed to be drained and would provide a highly porous substrate to allow fluid to flow freely to the weep holes.
The problem with this technique of placing the aggregate above and around the weep holes is that it is not widely practiced. The most common reasons for the lack of using aggregate over the weep holes are: lack of convenience, laziness, the mess of having to carry around gravel or break up tile, aggregate falling into the weep holes, and lack of stability in the mortar bed due to the loose gravel.
Whatever the various reasons might be for each neglectful contractor the fact remains that the majority of the showers built do not have the intended drainage construction in place. It is cumbersome to place the aggregate and keep them in place while installing the mortar bed over the pan and against the aggregate and drain. Since the loose aggregate is dimensionally unstable, it does not provide any solid support or stable backing for the adjacent and overlying mortar, either during the installation process or after it is cured. The mortar bed must be able to pack tightly against a firm surface during its placement in order to cure into a hard, stable material, and stay intact. The loose aggregate fails to provide a firm and stable surface.
However, all double seepage drains (known to this inventor) are designed to be dependent upon the aggregate for proper drainage and to function as designed. The whole double seepage drain industry is designed around the false assumption that all contractors are going to place aggregate over the weep holes of double seepage drains.
The loose aggregate further reduces the strength of the mortar bed by greatly reducing the depth of the mortar bed thickness in the area adjacent to the drain. There is nothing strong, continuous or dimensionally stable under the thin mortar bed in that area. Thus the integrity of the tile floor at that area is weakened. Often there are several small pieces of tile adjacent to the floor drain since small cuts have to be placed there in order to maintain the pattern of the floor tile. If loose agregate is placed over the weep holes, then these small tiles are often not bonded to anything strong, stable or solid and may come loose or even pull out of the floor. Though the reinforcing mesh will help deter this somewhat if used, it cannot completely overcome any of the various problems associated with the loose aggregate method.
In actuality the loose aggregate can contribute to clogging the drainage openings. The aggregate can fall into a weep hole and lodge there creating a partial or nearly complete obstruction of the opening. Some types of gravel which have a rounded shape will obstruct nearly all of a round or curved opening.
If an installer uses crushed tile pieces for the aggregate, he has little control over the sizes of the pieces he obtains from breaking the tile and thus has little control over what sizes of pieces will be placed over or fall into the weep holes. In addition the broken tile method can cause a leak to occur in the pan if it is punctured by a sharp piece of broken tile.
In general the aggregates commonly available to a tile contractor have had little or no grading done to them to sort the aggregate into appropriate sizes for use in this application.
In addition there is no convenient or practical way to prevent the aggregate from falling into the openings (weep holes) with this method. There needs to be a method or device for allowing the aggregate or other suitable drainage material to lay over and upon the openings without any particles falling into the openings, while at the same time not blocking access for water flow to the openings (weep holes).
Likewise, if no aggregate is used, very little water flow takes place into the weep holes and subsequently the mortar bed is not adequately drained. Furthermore if the mortar bed is allowed to come into direct contact with the weep holes, the fine particles and comparatively denser structure of the mortar bed effectively clog the weep holes. Even though the mortar bed is considered porous, for it to be effectively drained it should have a maximum surface area available for exposure to free water flow. The aggregate provides the free water flow and causes a greater surface area of the mortar bed to be exposed.
Even though the mortar bed is porous it would not be considered a medium for free water flow. Nor are the double seepage drains designed for the weep holes to come in direct contact with the mortar.
The need exists for a device that will be more readily and effectively used to solve this problem of draining the mortar bed, than the loose aggregate system. The lack of convenience and dimensional stability as well as the other problems already mentioned prove to be a great disadvantage of the loose aggregate method. These disadvantages lead to one of two possible unsatisfactory installations. If the loose aggregate is used then a lack of structural integrity and possible weep hole clog may occur. If in order to avoid the lack of structural integrity, and inconvenient hassle of obtaining and placing the loose aggregate, the installer chooses to place the mortar bed directly over the weep holes, then little or no drainage of the mortar bed will occur.
The weep holes that are currently manufactured in shower drains will not function as designed without a porous medium of some sort covering them. The medium needs to provide:
Whatever the precise merits, features and advantages of the loose aggregate method, it fails to adequately achieve or fulfill the purposes of the present invention.